The arrival of an advanced information society in recent years has desired computers to handle a large amount of data and has increasingly raised the importance and necessity of a data center that collectively manages a large number of computers.
A typical data center has a building constructed on a vast land, large-scale air-conditioning equipment, and large-scale electrical equipment. Hence, it takes a long time to complete a data center, and it is therefore difficult to speedily respond to the rise and fall of demand.
Against such a background, a module-type data center has been developed and put into practice. In a module-type data center, racks accommodating servers and the like, air-conditioning equipment, and electrical equipment are placed in a construction, called a container, of a predetermined size. Many types of module-type data centers take outside air into the container and cool the heat produced by the servers with the outside air, to thereby achieve reduction in the power used to cool the servers.    Patent Document 1: Japanese Laid-open Patent Publication No. 11-204974    Patent Document 2: Japanese Laid-open Patent Publication No. 2007-293936